Autotest.add_hook :initialize do |at|
  # Requires bundler before minitest since the minitest bundled with Ruby does
  # not support runners.
  at.testlib = 'bundler/setup minitest/unit'
  
  # Mappings from http://opensoul.org/blog/archives/2008/08/22/autotest-mapping-for-rails-test-conventions/.
  at.clear_mappings
  
  at.add_mapping %r%/^lib/(.*)\.rb$% do |_, m|
    possible = File.basename(m[1])
    files_matching %r%^test/.*(#{possible}_test|test_#{possible})\.rb$%
  end
  
  at.add_mapping(%r%^test/.*\.rb$%) { |filename, _| filename }
end